1. Field of the Invention
This invention relates to power cables having integral heater cables installed therewith and particularly to power cables having integral heaters for use in oil wells.
2. Description of Related art
When moving viscous oil from a well, particularly in shallow arctic oil wells, it is often beneficial to heat the oil to reduce its viscosity. To do this, a heater cable is installed in the well, along with a power cable that is run down the well to provide power to the submersible pump.
Heating circuits and power circuits typically have mutually exclusive design characteristics. Power cables are insulated with temperature sensitive materials and the power handling ability of these cables is temperature dependent. As a result, the common method of supplying power and heat to a well requires two penetrations in the well head; one for a power cable and one for an electric heater cable. This raises the cost of construction, and involves marking and monitoring two cables in the well.